1. Field of the Invention
This invention relates to tape measures in general and more particularly to reel type tape measuring tapes contained within an enclosure.
2. Brief Discussion of the Related Art
A tape measure represents a flexible form of linear rule, typically consisting of a ribbon or tape of cloth, plastic, fiberglass, or metallic strip of a uniform width containing measurement markings along its length. This style of measuring device provides advantages over a traditional fixed rule in that it is collapsible and easily stored in a coiled form.
One common form of tape measure that is well known in the construction industry retains the measuring tape by coiling it around a spool contained within a protective housing. The spool is pivotally mounted within the housing, allowing for free rotation therein. A retraction mechanism is then placed into the housing, allowing for the spool to be rotated within the housing for winding the tape upon the spool. The protective housing further contains a passageway allowing the tape to pass from the spool to outside of the protective housing. The preferred passageway is sized to be slightly larger than the width and thickness of the tape, rectangular in profile, and is located tangent to the diameter of the spool so as to allow the tape to pass without binding.
Tape measures, such as the construction model described above, are often used in locations where particulate matter such as sawdust and powders from metal or masonry products are present. In their typical application, tape measures are placed onto a work surface and a measurement is read between two or more points. When used in this manner debris contained on the work surface may adhere to the tape. Subsequent retraction of the tape then transports the debris inside the protective housing where it becomes trapped, unable to exit through the housing's small passageway. Once debris is trapped inside the tape measure's protective housing it will continue to accumulate and eventually foul the tape measure's internal mechanisms. Once fouling has occurred, the tape will no longer return to be stored on the spool rendering the device inoperable.
One prior art solution to the release of debris accumulation involves removal of the spool from the protective housing. Oftentimes, the protective housings of the construction models noted above contain two or more pieces which are separable. In order to clean the device, one may simply reverse the assembly process by releasing the fasteners which retain the housing. Once the tape and retraction mechanisms are exposed, they may then be cleaned.
However, once the case is opened and the spool is exposed the user may inadvertently release tension from the winding mechanism. This winding mechanism is oftentimes a pre-tensioned spring anchored between the housing and the spool. This spring applies a rotational bias causing the tape to coil upon the spool for storage. If this rotation bias is relieved, such as when the spring loses tension, the device will no longer retract. Since one end of the spring is often anchored to the housing itself, disassembly of the housing oftentimes relieve the spring's tension requiring the spring to be re-wound after the cleaning is completed. This rewinding of the spring is a complex and time consuming task. Oftentimes it is simply more economical to replace the entire tape measure rather then expend the time necessary to disassemble the old housing, clean and rewind the spring. As a result, there is a need to find a low cost method which allows for the particulate matter to be cleaned from the housing of a tape measure, preferably without the use of tools and which does not require disassembly of the housing or replacement of the reel cartridge inside.